Ill-posed medicine—an introduction to image registration

Image registration is the process of aligning two or more images of the same scene taken at different times, from different viewpoints and/or by different sensors. Image registration is a crucial step in imaging problems where the valuable information is contained in more than one image. Here, spatial alignment is required to properly integrate useful information from the separate images. It is the goal of this paper to give an overview on modern techniques in this area. It turns out that the registration problem is an inverse problem which does require a sound regularization and the use of proper models. Also, the numerics have to be done with great care. We will comment on these issues and supplement it by real life examples.